This invention pertains to the art of holder devices for a roller, slitting knife and more particularly to a holder device for a roller, scoring knife.
The invention is applicable to a holder device for a roller, slitting knife for slitting all types of materials and, more particularly, to a readily adjustable holder device for selective positioning while maintaining a relatively precise and optimum operational angle of attack. However, it will be appreciated to those skilled in the art that the invention can be readily adapted for use in other applications as, for example, where similar holder devices are employed for roller items.
Conventional roller knife holders are generally hydraulically or pneumatically pressurizable for adjusting the positioning and force of the roller knife against the material to be scored or slit. Typically a pressure operated blade holder for a roller cutting machine will include a selectively operable lowering piston assembly having a non-rotatable lowering piston rod. Mounted to the lowering piston rod is a setting piston assembly with a setting piston disposed for transverse movement of the lowering piston assembly. The piston rod of the setting piston is typically attached to a blade that operates as an upper blade and which may be operationally disposed oppositely of an associated lower blade of the roller cutting machine.
As already described in German Patent Specification Number 1,024,341 published Feb. 13, 1958, a plurality of such blade holders are typically mounted for axial displacement on a blade arm above the associated lower blades of a roller cutting machine. For changing the cutting width program, the upper blades are first displaced axially from the lower blades and then raised upwards and away from the lower blades. After adjusting new cutting widths on the blade arm, the upper blades are first lowered and then axially adjusted with respect to the associated lower blades which have been previously adjusted to the appropriate widths. It is particularly advantageous to maintain an angle of attack between the upper blades and the lower blades of the order of one degree in blade holders of this kind.
Various forms and types of roller slitting knife holders have heretofore been suggested and employed in the industry, all with varying degrees of success. It has been found that defects present in most prior knife holders are such that the devices themselves are of limited economic and practical value.
Prior holders have attempted to achieve maintenance of the one degree angle of attack by mounting the lowering piston rod such that rotation is inhibited by means of groove and spring members which are disposed between the lowering piston rod and its housing. Because of the fine tolerances required, the correct setting and configuration of conventional groove and spring guide means is costly to manufacture, install and maintain. In addition, the groove is typically longitudinally disposed of the lowering piston rod and may become clogged with the fine dust given off during cutting operations such that during the subsequent raising and lowering operations, the holder becomes particularly subject to jamming and inaccurate guidance. Furthermore, the lowering piston rod is typically weakened by the longitudinal groove and excessive pressures are localized at the groove which may promote system failure. The inclusion of the longitudinal groove also made it impossible for right or left handed blade holders to vary the angle of attack by plus one degree to minus one degree in either direction and therefore two different types of blade holders had to be manufactured and kept in store.
The present invention contemplates a new and improved device which overcomes all of the above referred to problems and others by providing a new holder for a roller slitting knife which is simple in design, economical to manufacture, readily adaptable to a plurality of uses with a variety of materials, easy to install, easy to adjust and remove and which provides improved guidance of a roller slitting knife during lowering and setting up of the knife.